JPH01202833A - Accurate xy stage device - Google Patents

Abstract

PURPOSE:To eliminate a decrease in a throughput and to decrease the working accuracy of a guide by measuring a pitch angle error, a rolling angle error, and a yawing angle error at the positions of a stage, and so controlling the stage that the angle variation values become zero. CONSTITUTION:Stages 1, 2 are driven perpendicularly by a motor 8 and feed threads 9, and the position of a wafer stage is measured by a laser interferometer 7. The pitching variation upon movement of the stages 1, 2 is detected by the difference of the stage positions measured by laser interferometers 7a, 7b, the rolling variation is detected by the difference of the stage positions measured by lease interferometers 7c, 7d, and yawing variation is detected by the difference of the stage positions measured by laser interferometers 7d, 7e. Angle error correcting stages 4-6 are provided on the stages 1, 2, thereby correcting the pitching, rolling and yawing errors obtained by the interferometers. Accordingly, an influence to be made on the alignment can be set to substantially zero. Thus, the working accuracy of a guide is decreased, and a decrease in its throughput is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high-precision XY stage device in a positioning device #t# of a semiconductor manufacturing device.

(Prior Art) In a table device for a semiconductor exposure apparatus used in vLSI manufacturing, one positioning accuracy is required to be 0.05 μm or less. In such an ultra-precise positioning device, it is common to use a laser interferometer to measure the position of the mirror on the wafer table in the X and Y axes, and then perform positioning using a servo circuit. However, in this method, there are angle changes #h1 of the stage called yawing angle error, pitching angle error, and rolling angle error due to table movement.

It is necessary to keep these error components to a very small level.8 Normally, even if a guide is manufactured with high precision, if the rolling shaft or bearing etc. A method for correcting the yaw angle error has been proposed. This is done by measuring the mirror surface on the wafer table at two points for one axis, subtracting the position of the two points when the table moves, and taking the yawing error as the yawing error. It applies a servo to. In this way, position errors due to table yawing errors can be eliminated.

However, 1. For example, if there is a pitching error of 5 seconds when moving the chip, and the distance between the exposed surface of the wafer and the mirror measured by the laser interferometer is 2 mm, then 0.
Conventionally, this error, which causes a position error of 0.5 μm, was reduced by increasing the machining sliding degree of the guide by an empirical value f, and was eliminated by TTL alignment. The production thereof requires time and high cost, and the throughput is significantly reduced compared to TTL alignment.

(Problems to be Solved by the Invention) The present invention is an attempt to solve the above-mentioned problems, and eliminates the throughput drop due to TTL alignment during chip exposure and improves the roughness of the guide based on experience. The present invention provides an advanced XY stage device equipped with an angle correction control device that can be omitted.

[Structure of the invention]

(Means for Solving the Problems) In the present invention, the pitching angle error, rolling angle error, and yaw angle error are measured at each position of the stage, and the stage is controlled so that the angular fluctuation values thereof are set to zero. .

(Function) Pitching angle error and Q-ring angle error are determined by measuring the stage position at two points between the mirrors on the wafer table using a laser interferometer, and detecting the difference between the stage positions at the two points. demand. Now, the resolution of the laser interferometer is about 0.01 μm.
If the distance between the two points is 30 mnn, it will take approximately 0.1 seconds. Assuming that the distance between the exposed surface of the wafer and the mirror measurement position using the laser interferometer is 2 mm, we calculate the production error for the LSI chip again and find that it is approximately 0°001 μm.
In other words, pitching and rolling fluctuations can be corrected at M degrees, which is close to the resolution of the laser interferometer, so that the influence on position alignment can be reduced to almost nothing.

(Embodiment) FIG. 1 is an embodiment of a high-precision XY stage using a pitching, rolling, and yawing correction mechanism according to the present invention. Also, Figure 2 shows pitching.

This is an example of a rolling and yawing correction restraint circuit. Stages 1 and 2 are orthogonally driven by a motor 8 and a feed screw 9#. The position of the wafer stage is measured by a laser interferometer 7. Pitching fluctuations due to movement of the stage 1.2 are detected by the difference in stage position measured by laser interferometers 7a and 7b, and rolling fluctuations are detected by laser interferometer 7c.

Yawing fluctuation is detected by the difference in stage position measured by laser interferometers 7d and 7e.

There are angular error correction stages 4 to 6 on stages 1 and 2, which correct pitching, rolling, and yawing errors determined by a laser interferometer. First, the up/down ('UP-DOWN) pulse of the laser interferometer 7b is activated.
UP/DOWN) Force is counted and stored in the latch 11a. In addition, the up/down (UP-DOWN) pulse of the laser interferometer 7c is
(Stored in UP/DOWN3 counter 1.Ob. The data of latches 10a and 10b are subtracted by subtractor 12 to obtain each angle error fluctuation value. This value is passed through latch 13 to D
/A converter 14 converts it into an analog signal. This analog signal is amplified by an amplifier 15, and a low pass filter 1
6 attenuates the high frequency range, and a power amplifier 17 drives the actuator. This moves each angle error correction stage for pitching and rolling. Correct yaw variation.

〔Effect of the invention〕

By using the above-mentioned configuration, it is possible to minimize the positioning error caused by the angular error without having to extremely increase the sensitivity of the guide and without reducing the throughput due to transfer by TTL alignment.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of a high-precision XY stage device according to the present invention, and Fig. 2 is a circuit showing an embodiment of the control circuit thereof. 1...Y-axis stage, 2...X-axis stage, 3...
・2-axis stage, 4... Pitching angle stage, 5.
... Rolling angle stage, 6... Yawing angle stage. 7... Laser interferometer, 8... DC motor, 9...
Feed screw, 10...UP/DOWN counter, 11.
...Latch, 12...Subtractor% 13...U Vchi,
14...D/A converter% 15...Amplifier, 1
6...Low pass filter. 17...Power amplifier% 18...Right angle mirror. Agent Patent Attorney Noriyuki Chika Yudo Hikaru Matsuyama

Claims (2)

[Claims] (1) In an XY table for semiconductor exposure equipment, a drive mechanism for independently moving the table device in the Z-axis direction, pitching angle direction, rolling angle direction, and yawing angle direction, and the X-axis position, Y-axis position of the table, Measuring means for constantly detecting Z-axis position, pitching angle error, rolling angle error, and yaw angle error; A high-precision XY stage device characterized by comprising a servo mechanism that reduces the angle fluctuation value to zero by using a mechanism that drives in the angular direction, rolling angular direction, and yawing angular direction. (2) The measurement means is a laser interference measurement system, and in the mirror as the measurement target of this laser interference measurement system, it is sufficient to determine two points on the Z axis perpendicular to the movement axis of the high precision XY stage. The high-precision XY stage device according to claim 1, characterized in that it has a width.